September 1, 2015

Mount Caubvick Glacier Retreat, Labrador

Posted by Mauri Pelto

Mount Caubvick is in the Torngat Mountains of Labrador 35 km inland of the Atlantic Ocean and south of Nachvak Fjord. Way et al (2014) identified 105 active glaciers that had flow indicators in these mountains.  The mean elevation of these glaciers is quite low at 776 meters above sea level. The radiational shading and higher accumulation from protected cirque locations and proximity to the ocean are key to the low elevations. The elevation of the glaciers around Mount Caubvick is higher. Here we use Landsat images from 1992, 1997 and 2015 to identify response to climate change. The annual layers preserved in the glacier ice are evident in glacier B,C and E.

caubvick

2013 Google Earth image of Mount Caubvick, Torngat Mountains, Labrador.

In 1992 Glacier A terminates at the red arrow in an expanding lake. Glacier C terminates at the yellow arrow in a just forming glacial lake.  Glacier E terminates at the purple arrow in a glacial lake that is similar in length to the glacier. In 2015 each lake has notably expanded.  The arrows are in the same locations in the 2015 image.  At the red arrow, Glacier A has retreated 200 m, which is 20% of its entire length. Glacier C, yellow arrow has retreated 250 m, 40% of the total glacier length.  At the purple arrow, Glacier D has retreated 225 m, which is 35% of its total length.  The retreat of Glacier B and E is less clear as the terminus locations are hard to determine in 1992.  What is most evident is the reduction in ice area at the higher elevations of the glaciers noted by the green arrows. In 1997 there is little expansion of the three lakes since 1992, indicating most of the retreat has been in the last 18 years.  Glacier B provides a good snapshot of annual layers.  The black arrow indicates the lack of an accumulation zone, without which a glacier cannot survive (Pelto, 2010). The red arrow indicates a band of annual layers that marks what had been the typical snowline Indeed none of the glaciers in 2015 in either the 2013 Google Earth image or 2015 Landsat have significant retained accumulation, indicating none can survive current climate. Way et al (2014) figure 4 indicates an example of the same snowline setup on a different glacier near Ryans Bay. .  it is evident that in the last decade firn and snow are not retained consistently. Sharp et al (2014) indicate in Figure 52 the mass loss of Canadian Arctic glaciers in general, that parallels that of Labrador.

caubvick compare

1992-2015 Landsat comparison of Mount Caubvick glaciers

torngat 2014 annual layers

Glacier B with numerous annual layers with the snowline indicates by red arrow and lack of accumulation black arrow.

torngat cirque layers

 

Glacier C annual layers.